The present invention relates to output devices, and in particular to output devices employed in displays.
Thin film transistor liquid crystal displays (TFT-LCDs) are applied in a variety of electronic devices, such as mobile phones. Recently, the volume of TFT-LCD panels is increased, resulting in the undesired increase of loading on drivers of TFT-LCDs. Moreover, since resolution and operating frequency of large volume TFT-LCD panels are increased, the drivers have to output correct driving signals in shorter time.
In conventional TFT-LCD panels, output devices within drivers have a low slew rate, so that the drivers cannot output correct driving signals in a short time. FIG. 1 shows an output device in a driver of a conventional TFT-LCD panel. The output driver 1 comprises an amplifier 10 and a capacitor 11. The capacitor 11 serves as a compensation element to ensure that the amplifier 10 operates stably while decreasing the slew rate of the amplifier 10. Referring to FIG. 2, a solid line represents an ideal driving signal while a dashed line represents a driving signal SD output by the amplifier 10. Since the capacitor 11 limits the slew rate of the amplifier 10, the rise time of the driving signal SD is longer. Thus, in a large TFT-LCD panel, a driver cannot output correct driving signal SD in a short time, so that the TFT-LCD panel displays incorrect images.